SAP HCM synchronization performance problem

Question

To fulfill customer requirements, we need to use data from SAP tables, that are not synchronized by OOTB connector. 
 To read these tables we used SAP Schema Extension functionality. Initial synchronization works more or less fast (a hew hours), but subsequent synchronization takes tremendous amount of time - e g. a few days for a table that contains 200 000 records. In stdio logs I can see that data from SAP is read fast (a few minutes), but then connector tries to find matching objects (in some case matching rule includes 8 attributes) and it is really slow. 
 Has anybody encountered this problem? 
 
 Has anybody used SAP Schema Extension functionality? How long does it usually take to synchronize a table with 100 000 records? 
 
 Regards, 
 Ivan

mekindad · Answer

I have a table with 1.2 MIO records but use OOTB mappings (SAP Authorization function assignments). It takes first time up to 4 hours but after that with revision functionality goes down to one hour. 
 Matching Rule is always a problem in this case. 
 From experience I would suggest a Two stage sync: 
 1. Sync whole data from SAP to 1IM without a lot of rules (just raw sync) 
 2. Create another sync from 1IM to 1IM ;-) to get the data where You want it to be!